Aminocycloalkyl cinnamide compounds for arrhythmia and analgesics and anesthetics

ABSTRACT

Aminocycloalkyl cinnamide compounds (I) are disclosed. The compounds of the present invention may be incorporated in compositions and kits. The present invention also discloses a variety of in vitro and in vivo uses for the compounds and compositions, including the treatment of arrhythmia and the production of local analgesia and anesthesia. n=1–4; R 1 , R 2 , R 3 , R 4 , R 5 , R 13 , X and A are as in claim ( 1 ).

This application is a 371 of PCT/CA00/00217 filed 3 Mar. 2000.

This application claims the benefit of Provisional Application No.60/122,858, filed Mar. 4, 1999.

TECHNICAL FIELD

The present invention is generally directed toward aminocycloalkylcinnamide compounds, pharmaceutical compositions and kits containing theaminocycloalkyl cinnamide compounds, and therapeutic uses thereof.

BACKGROUND OF THE INVENTION

Arrhythmia is a variation from the normal rhythm of the heart beat andgenerally represents the end product of abnormal ion-channel structure,number or function. Both atrial arrhythmias and ventricular arrhythmiasare known. The major cause of fatalities due to cardiac arrhythmias isthe subtype of ventricular arrhythmias known as ventricular fibrillation(VF). Conservative estimates indicate that, in the U.S. alone, each yearover one million Americans will have a new or recurrent coronary attack(defined as myocardial infarction or fatal coronary heart disease).About 650,000 of these will be first heart attacks and 450,000 will berecurrent attacks. About one-third of the people experiencing theseattacks will die of them. At least 250,000 people a year die of coronaryheart disease within 1 hour of the onset of symptoms and before theyreach a hospital. These are sudden deaths caused by cardiac arrest,usually resulting from ventricular fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia seen in clinicalpractice and is a cause of morbidity in many individuals Its prevalenceis likely to increase as the population ages and it is estimated that3–5% of patients over the age of 60 years have AF. While AF is rarelyfatal, it can impair cardiac function and is a major cause of stroke.

Antiarrhythmic agents have been developed to prevent or alleviatecardiac arrhythmia. For example, Class I antiarrhythmic compounds havebeen used to treat supraventricular arrhythmias and ventriculararrhythmias. Treatment of ventricular arrhythmia is very important sincesuch an arrhythmia can be fatal. Serious ventricular arrhythmias(ventricular tachycardia and ventricular fibrillation) occur most oftenin the presence of myocardial ischemia and/or infarction. Ventricularfibrillation often occurs in the setting of acute myocardial ischemia,before infarction fully develops. At present, there is no satisfactorypharmacotherapy for the treatment and/or prevention of ventricularfibrillation during acute ischemia. In fact, many Class I antiarrhythmiccompounds may actually increase mortality in patients who have had amyocardial infarction.

Class Ia, Ic and III antiarrhythmic drugs have been used to convertrecent onset AF to sinus rhythm and prevent recurrence of the arrhythmia(Nattel S., Hadjis T., Talajic M., Drugs 48(3):345–71, 1994). However,drug therapy is often limited by adverse effects, including thepossibility of increased mortality, and inadequate efficacy (Nattel S.,Cardiovascular Research. 37(3):567–77, 1998). Conversion rates for ClassI antiarrhythmics range between 50–90% (Steinbeck G., Remp T., HoffmannE., Journal of Cardiovascular Electrophysiology. 9(8 Suppl):S104–8,1998). Class III antiarrhythmics appear to be more effective forterminating atrial flutter than for AF and are generally regarded asless effective than Class I drugs for terminating AF (Capucci A.,Aschieri D., Villani G. Q., Drugs &Aging 13(1):51–70, 1998). Examples ofsuch drugs include ibutilide, dofetilide and sotalol. Conversion ratesfor these drugs range between 30–50% for recent onset AF (Capucci A.,Aschieri D. Villani G. Q., Drugs &Aging 13(1):51–70, 1998), and they arealso associated with a risk of the induction of Torsades de Pointesventricular tachyarrhythmias. For ibutilide, the risk of ventricularproarrhythmia is estimated at ˜4.4%, with ˜1.7% of patients requiringcardioversion for refractory ventricular arrhythmias (Kowey P. R.,VanderLugt J. T., Luderer J. R., American Journal of Cardiology78(8A):46–52, 1996). Such events are particularly tragic in the case ofAF as this arrhythmia is rarely fatal in and of itself.

Therefore, there is a need in the art to identify new antiarrhythmictreatments, for both ventricular arrhythmias as well as for atrialarrhythmias. The present invention fulfills this need, and furtherprovides other related advantages.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides aminocycloalkylcinnamide compounds of formula (I), or a solvate or pharmaceuticallyacceptable salt thereof:

wherein, independently at each occurrence,

n is selected from 1, 2, 3 and 4;

X is selected from a direct bond, and —C(R₆,R₁₄)—Y—,

Y is selected from a direct bond, O, S, and C₁–C₄alkylene;

R₁₃ is selected from hydrogen, C₁–C₆alkyl, C₃–C₈cycloalkyl, aryl, andbenzyl;

R₁ and R₂ are independently selected from hydrogen, C₁–C₈alkyl,C₃–C₈alkoxyalkyl, C₁–C₈hydroxyalkyl, and C₁–C₁₂aralkyl; or

R₁ and R₂, when taken together with the nitrogen atom to which they aredirectly attached in formula (I), form a ring denoted by formula (II):

wherein the ring of formula (II) is formed from the nitrogen as shown aswell as three to nine additional ring atoms independently selected fromcarbon, nitrogen, oxygen, and sulfur; where any two adjacent ring atomsmay be joined together by single or double bonds, and where any one ormore of the additional carbon ring atoms may bear one or twosubstituents selected from hydrogen, hydroxy, C₁–C₃hydroxyalkyl, oxo,C₂–C₄acyl, C₁–C₃alkyl, C₂–C₄alkylcarboxy, C₁–C₃alkoxy,C₁–C₂₀alkanoyloxy, or may form a Spiro five- or six-memberedheterocyclic ring containing one or two heteroatoms selected from oxygenand sulfur; and any two adjacent additional carbon ring atoms may befused to a C₃–C₈carbocyclic ring, and any one or more of the additionalnitrogen ring atoms may bear substituents selected from hydrogen,C₁–C₆alkyl, C₂–C₄acyl, C₂–C₄hydroxyalkyl and C₃–C₈alkoxyalkyl; or

R₁ and R₂, when taken together with the nitrogen atom to which they aredirectly attached in formula (I), may form a bicyclic ring systemselected from 3-azabicyclo[3.2.2]nonan-3-yl,2-azabicyclo[2.2.2]octan-2-yl, 3-azabicyclo[3.1.0]hexan-3-yl and3-azabicyclo[3.2.0]heptan-3-yl;

R₃ and R₄ are independently attached to the cycloalkyl ring shown informula (I) at other than the 1 and 2 positions and are independentlyselected from hydrogen, hydroxy, C₁–C₆alkyl and C₁–C₆alkoxy, and, whenboth R₃ and R₄ are attached to the same cycloalkyl ring atom, maytogether form a spiro five- or six-membered heterocyclic ring containingone or two heteroatoms selected from oxygen and sulfur;

R₅, R₆ and R₁₄ are independently selected from hydrogen, C₁–C₆alkyl,aryl and benzyl, or R₆ and R₁₄, when taken together with the carbon towhich they are attached, may form a spiro C₃–C₅cycloalkyl;

A is selected from C₅–C₁₂alkyl, a C₃–C₁₃carbocyclic ring, and ringsystems selected from formulae (III), (IV), (V), (VI), (VII) and (VIII):

where R₇, R₈ and R₉ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, aryl and N(R₁₅,R₁₆)where R₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl and C₁–C₆alkyl;

where R₁₀ and R₁₁ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, and N(R₁₅,R₁₆) whereR₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl, and C₁–C₆alkyl;

where R₁₂ is selected from bromine, chlorine, fluorine, carboxy,hydrogen, hydroxy, hydroxymethyl, methanesulfonamido, nitro, sulfamyl,trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl, C₁–C₆alkoxy,C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, and N(R₁₅,R₁₆) where R₁₅ and R₁₆are independently selected from hydrogen, acetyl, methanesulfonyl, andC₁–C₆alkyl; and Z is selected from CH, CH₂, O, N and S, where Z may bedirectly bonded to the carbon atom in formula (I) that is shown directlybonded to “A” when Z is CH or N, or Z may be directly bonded to R₁₇ whenZ is N, and R₁₇ is selected from hydrogen, C₁–C₆alkyl, C₃–C₈cycloalkyl,aryl and benzyl;

including isolated enantiomeric, diastereomeric and geometric isomersthereof, and mixtures thereof;

with the proviso that, said compound of formula (I) may not be(1R,2S)/(1S,2R)-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-3,4-dichlorocinnamide.

In other embodiments, the present invention provides a composition ormedicament that includes a compound according to formula (I) without theproviso in combination with a pharmaceutically acceptable carrier,diluent or excipient, and further provides a method for the manufactureof a composition or medicament that contains a compound according toformula (I) without the proviso.

In other embodiments, the present invention provides pharmaceuticalcompositions that contain at least one compound of formula (I) withoutthe proviso in an amount effective to treat a disease or condition in awarm-blooded animal suffering from or having the disease or condition,and/or prevent a disease or condition in a warm-blooded animal thatwould otherwise occur, and further contains at least onepharmaceutically acceptable carrier, diluent or excipient. The inventionfurther provides for methods of treating a disease or condition in awarm-blooded animal suffering from or having the disease or condition,and/or preventing a disease or condition from arising in a warm-bloodedanimal, wherein a therapeutically effective amount of a compound offormula (I) without the proviso, or a composition containing a compoundof formula (I) without the proviso is administered to a warm-bloodedanimal in need thereof. The diseases and conditions to which thecompounds, compositions and methods of the present invention haveapplicability are as follows: arrhythmia, diseases of the centralnervous system, convulsions, epileptic spasms, depression, anxiety,schizophrenia, Parkinson's disease, respiratory disorders, cysticfibrosis, asthma, cough, inflammation, arthritis, allergies,gastrointestinal disorders, urinary incontinence, irritable bowelsyndrome, cardiovascular diseases, cerebral or myocardial ischemias,hypertension, long-QT syndrome, stroke, migraine, ophthalmic diseases,diabetes mellitus, myopathies, Becker's myotonia, myasthenia gravis,paramyotonia congentia, malignant hyperthermia, hyperkalemic periodicparalysis, Thomsen's myotonia, autoimmune disorders, graft rejection inorgan transplantation or bone marrow transplantation, heart failure,hypotension, Alzheimer's disease or other mental disorder, and alopecia.

In another embodiment, the present invention provides a pharmaceuticalcomposition containing an amount of a compound of formula (I) withoutthe proviso effective to produce local analgesia or anesthesia in awarm-blooded animal in need thereof, and a pharmaceutically acceptablecarrier, diluent, or excipient. The invention further provides a methodfor producing, local analgesia or anesthesia in a warm-blooded animalwhich includes administering to a warm-blooded animal in need thereof aneffective amount of a compound of formula (I) without the proviso or apharmaceutical composition containing a compound of formula (I) withoutthe proviso. These compositions and methods may be used to relieve orforestall the sensation of pain in a warm-blooded animal.

In another embodiment, the present invention provides a pharmaceuticalcomposition containing an amount of a compound of formula (I) withoutthe proviso effective to enhance the libido in a warm-blooded animal inneed thereof, and a pharmaceutically acceptable carrier, diluent, orexcipient. The invention further provides a method for enhancing libidoin a warm-blooded animal which includes administering to a warm-bloodedanimal in need thereof an effective amount of a compound of formula (I)without the proviso or a pharmaceutical composition containing acompound of formula (I) without the proviso. These compositions andmethods may be used, for example, to treat a sexual dysfunction, e.g.,impotence in males, and/or to enhance the sexual desire of a patientwithout a sexual dysfunction. As another example, the therapeuticallyeffective amount may be administered to a bull (or other breedingstock), to promote increased semen ejaculation, where the ejaculatedsemen is collected and stored for use as it is needed to impregnatefemale cows in promotion of a breeding program.

In another embodiment, the present invention provides a compound offormula (I) without the proviso or composition containing a compound offormula (I) without the proviso, for use in methods for eithermodulating ion channel activity in a warm-blooded animal or formodulating ion channel activity in vitro.

These and other embodiments of the present invention will become evidentupon reference to the following drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C illustrates reaction sequences further described inExamples 1, 2 and 3, respectively, for preparing aminocycloalkylcinnamide compounds of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, the present invention is directed to aminocycloalkylcinnamide compounds, pharmaceutical compositions containing theaminocycloalkyl cinnamide compounds, and various uses for the compoundand compositions. Such uses include modulation of ion channels in vitroor in vivo, the treatment of arrhythmias, the production of anesthesia,and other uses as described herein. An understanding of the presentinvention may be aided by reference to the following definitions andexplanation of conventions used herein.

Definitions and Conventions

The aminocycloalkyl cinnamide compounds of the invention have acinnamide group

at position 1 of a cycloalkyl ring, and an amine nitrogen atom atposition 2 of the cycloalkyl ring. The cycloalkyl ring is eithercyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl, with other positionsnumbered in corresponding order as shown below in structure (A) forcyclopentane, structure (B) for cyclohexane, structure (C) forcycloheptane, and structure (D) for cyclooctane:

The bonds from the cycloalkyl ring to the 1-cinnamide and 2-amine groupsin the above formula may be relatively disposed in either a cis or transrelationship. In a preferred embodiment of the present invention, thestereochemistry of the amine and cinnamide substituents of thecycloalkyl ring is either (R,R)-trans or (S,S)trans. In anotherpreferred embodiment the stereochemistry is either (R,S)-cis or(S,R)-cis.

In the formulae depicted herein, a bond to a substituent and/or a bondthat links a molecular fragment to the remainder of a compound may beshown as intersecting one or more bonds in a ring structure. Thisindicates that the bond may be attached to any one of the atoms thatconstitutes the ring structure, so long as a hydrogen atom couldotherwise be present at that atom. Where no particular substituent(s) isidentified for a particular position in a structure, then hydrogen(s) ispresent at that position. For example, compounds of the inventioncontaining the cinnamide group

where A equals formula (III)

are intended to encompass compounds having the group (E) (where, forconvenience, only one possible geometric isomer is shown):

where the group (E) is intended to encompass groups wherein any ringatom that could otherwise be substituted with hydrogen, may instead besubstituted with either R₇, R₈ or R₉, with the proviso that each of R₇,R₈ and R₉ appears once and only once on the ring. Ring atoms that arenot substituted with any of R₇, R₈ or R₉ are substituted with hydrogen.In those instances where the invention specifies that a non-aromaticring is substituted with more than one R group, and those R groups areshown connected to the non-aromatic ring with bonds that bisect ringbonds, then the R groups may be present at different atoms of the ring,or on the same atom of the ring, so long as that atom could otherwise besubstituted with a hydrogen atom.

Likewise, where the invention specifies compounds containing thecinnamide group

where A equals the aryl group (VI)

the invention is intended to encompass compounds wherein

is joined through the single bond of ═CH— to the aryl group (VI) at anyatom which forms the aryl group (VI) so long as that atom of group (VI)could otherwise be substituted with a hydrogen atom. Thus, there areseven positions (identified with the letters “a” through “g”) instructure (VI) where the ═CH— group could be attached, and it isattached at one of those seven positions. The R₁₂ group would occupy oneand only one of the remaining six positions, and hydrogen atoms would bepresent in each of the five remaining positions. It is to be understoodthat when Z represents a divalent atom, e.g., oxygen or sulfur, then Zcannot be directly bonded to

When the invention specifies the location of an asymmetric divalentradical, then that divalent radical may be positioned in any possiblemanner that provides a stable chemical structure. For example, forcompounds containing the cinnamide group

where X is C(R₁₄,R₆)—Y—, the invention provides compounds having boththe

and

groups.

A wavy bond from a substituent to the central cycloalkyl ring indicatesthat the substituent may be located on either side of the plane of thecentral ring.

The compounds of the present invention contain at least two asymmetriccarbon atoms and thus exist as enantiomers and diastereomers. Unlessotherwise noted, the present invention includes all enantiomeric anddiastereomeric forms of the aminocycloalkyl cinnamide compounds of theinvention. Pure stereoisomers, mixtures of enantiomers and/ordiastereomers, and mixtures of different compounds of the invention areincluded within the present invention. Thus, compounds of the presentinvention may occur as racemates, racemic mixtures and as individualdiastereomers, or enantiomers with all isomeric forms being included inthe present invention. A racemate or racemic mixture does not imply a50:50 mixture of stereoisomers.

The phrase “independently at each occurrence” is intended to mean (i)when any variable occurs more than one time in a compound of theinvention, the definition of that variable at each occurrence isindependent of its definition at every other occurrence; and (ii) theidentity of any one of two different variables (e.g., R₁ within the setR₁ and R₂) is selected without regard the identity of the other memberof the set. However, combinations of substituents and/or variables arepermissible only if such combinations result in stable compounds.

In accordance with the present invention and as used herein, thefollowing terms are defined to have the following meanings, unlessexplicitly stated otherwise:

“Acid addition salts” refers to those salts which retain the biologicaleffectiveness and properties of the free bases and which are notbiologically or otherwise undesirable, formed with inorganic acids suchas hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid,phosphoric acid and the like, or organic acids such as acetic acid,propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid,malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid,benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid,ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and thelike.

“Acyl” refers to branched or unbranched hydrocarbon fragments terminatedby a carbonyl —(C═O)— group containing the specified number of carbonatoms. Examples include acetyl [CH₃C(═O)—, a C₂acyl] and propionyl[CH₃CH₂C(═O)—, a C₃acyl].

“Alkanoyloxy” refers to an ester substituent wherein the non-carbonyloxygen is the point of attachment to the molecule. Examples includepropanoyloxy [(CH₃CH₂C(═O)—O—, a C₃alkanoyloxy] and ethanoyloxy[CH₃C(═O)—O—, a C₂alkanoyloxy].

“Alkoxy” refers to an O-atom substituted by an alkyl group, for example,methoxy [—OCH₃, a C₁alkoxy].

“Alkoxyalkyl” refers to an alkylene group substituted with an alkoxygroup. For example, methoxyethyl [CH₃OCH₂CH₂—] and ethoxymethyl(CH₃CH₂OCH₂—] are both C₃alkoxyalkyl groups.

“Alkoxycarbonyl” refers to an ester substituent wherein the carbonylcarbon is the point of attachment to the molecule. Examples includeethoxycarbonyl [CH₃CH₂C(═O)—, a C₃alkoxycarbonyl] and methoxycarbonyl[CH₃₀C(═O)—, a C₂alkoxycarbonyl].

“Alkyl” refers to a branched or unbranched hydrocarbon fragmentcontaining the specified number of carbon atoms and having-one point ofattachment. Examples include n-propyl (a C₃alkyl), iso-propyl (also aC₃alkyl), and t-butyl (a C₄alkyl).

“Alkylene” refers to a divalent radical which is a branched orunbranched hydrocarbon fragment containing the specified number ofcarbon atoms, and having two points of attachment. An example ispropylene [—CH₂CH₂CH₂—, a C₃alkylene].

“Alkylcarboxy” refers to a branched or unbranched hydrocarbon fragmentterminated by a carboxylic acid group [—COOH]. Examples includecarboxymethyl [HOOC—CH₂—, a C₂alkylcarboxy] and carboxyethyl[HOOC—CH₂CH₂—, a C₃alkylcarboxy].

“Aryl” refers to aromatic groups which have at least one ring having aconjugated pi electron system and includes carbocyclic aryl,heterocyclic aryl (also known as heteroaryl groups) and biaryl groups,all of which may be optionally substituted. Carbocyclic aryl groups aregenerally preferred in the compounds of the present invention, wherephenyl and naphthyl groups are preferred carbocyclic aryl groups.

“Aralkyl” refers to an alkylene group wherein one of the points ofattachment is to an aryl group. An example of an aralkyl group is thebenzyl group [C₆H₅CH₂—, a C₇aralkyl group].

“Cycloalkyl” refers to a ring, which may be saturated or unsaturated andmonocyclic, bicyclic, or tricyclic formed entirely from carbon atoms. Anexample of a cycloalkyl group is the cyclopentenyl group (C₅H₇—), whichis a five carbon (C₅) unsaturated cycloalkyl group.

“Carbocyclic” refers to a ring which may be either an aryl ring or acycloalkyl ring, both as defined above.

“Carbocyclic aryl” refers to aromatic groups wherein the atoms whichform the aromatic ring are carbon atoms. Carbocyclic aryl groups includemonocyclic carbocyclic aryl groups such as phenyl, and bicycliccarbocyclic aryl groups such as naphthyl, all of which may be optionallysubstituted.

“Cinnamide” refers to a group of the

which includes both the ‘conventional cinnamide’ group when X is adirect bond and the ‘unconventional cinnamide’ group when X isC(R₁₄,R₆)—Y—.

“Heteroatom” refers to a non-carbon atom, where boron, nitrogen, oxygen,sulfur and phosphorus are preferred heteroatoms, with nitrogen, oxygenand sulfur being particularly preferred heteroatoms in the compounds ofthe present invention.

“Heteroaryl” refers to aryl groups having from 1 to 9 carbon atoms andthe remainder of the atoms are heteroatoms, and includes thoseheterocyclic systems described in Handbook of Chemistry and Physics,49th edition, 1968, R. C. Weast, editor; The Chemical Rubber Co.,Cleveland, Ohio. See particularly Section C, Rules for Naming OrganicCompounds, B. Fundamental Heterocyclic Systems. Suitable heteroarylsinclude furanyl, thienyl, pyridyl, pyrrolyl, pyrimidyl, pyrazinyl,imidazolyl, and the like.

“Hydroxyalkyl” refers to a branched or unbranched hydrocarbon fragmentbearing an hydroxy (—OH) group. Examples include hydroxymethyl (—CH₂OH,a C₁hydroxyalkyl) and 1-hydroxyethyl (—CHOHCH₃, a C₂hydroxyalkyl).

“Thioalkyl” refers to a sulfur atom substituted by an alkyl group, forexample thiomethyl (CH₃S—, a C₁thioalkyl).

“Modulating” in connection with the activity of an ion channel meansthat the activity of the ion channel may be either increased ordecreased in response to administration of a compound or composition ormethod of the present invention. Thus, the ion channel may be activated,so as to transport more ions, or may be deactivated or blocked, so thatfewer or no ions, respectively, are transported by the channel.

“Pharmaceutically acceptable carriers” for therapeutic use are wellknown in the pharmaceutical art, and are described, for example, inRemingtons Pharmaceutical Sciences, Mack Publishing Co. (A. R. Gennaroedit. 1985). For example, sterile saline and phosphate-buffered salineat physiological pH may be used. Preservatives, stabilizers, dyes andeven flavoring agents may be provided in the pharmaceutical composition.For example, sodium benzoate, sorbic acid and esters of p-hydroxybenzoicacid may be added as preservatives. Id. at 1449. In addition,antioxidants and suspending agents may be used. Id.

“Pharmaceutically acceptable salt” refers to salts of the compounds ofthe present invention derived from the combination of such compounds andan organic or inorganic acid (acid addition salts) or an organic orinorganic base (base addition salts). The compounds of the presentinvention may be used in either the free base or salt forms, with bothforms being considered as being within the scope of the presentinvention.

The “therapeutically effective amount” of a compound of the presentinvention will depend on the route of administration, the type ofwarm-blooded animal being treated, and the physical characteristics ofthe specific warm-blooded animal under consideration. These factors andtheir relationship to determining this amount are well known to skilledpractitioners in the medical arts. This amount and the method ofadministration can be tailored to achieve optimal efficacy but willdepend on such factors as weight, diet, concurrent medication and otherfactors which those skilled in the medical arts will recognize.

Compositions described herein as “containing a compound of formula (I)”encompass compositions that contain more than one compound of formula(I).

Compounds of the Present Invention

The compounds of the present invention are amines which may berepresented by formula (I):

Compounds of formula (I) are aminocycloalkyl cinnamides. Morespecifically, these aminocycloalkyl cinnamides are substituted atposition 2 of a cycloalkyl ring with an amine group —NR₁R₂. Thecycloalkyl ring may also be substituted with additional substituents(designated as R₃ and R₄) as described in more detail below. In formula(I), n is selected from 1, 2, 3 and 4, and represents a number of carbonatoms such that when n equals 1, the ring shown in Formula (I) is asubstituted cyclopentane (i.e., a cyclopentyl group), when n equals 2,the ring shown in Formula (I) is a cyclohexane (i.e., a cyclohexylgroup), when n equals 3, the ring shown in Formula (1) is a substitutedcycloheptane (i.e., a cycloheptyl group), and when n equals 4, the ringshown in Formula (I) is a substituted cyclooctane (i.e., a cyclooctylgroup). Examples of specific embodiments of compounds represented byformula (I) are described below

Depending upon the selection of substituents R_(1 and R) ₂, Thecompounds of formula (I) may be primary, secondary, or tertiary amines(i.e., both R₁ and R₂ are hydrogen, only one of R₁ and R₂ is hydrogen,or neither of R₁ and R₂ are hydrogen, respectively). Where the amine istertiary, it may be a cyclic amine. Amine substituents R₁ and R₂ may beindependently selected from substituents which include hydrogen, alkylgroups containing from one to eight carbon atoms (i.e., C₁–C₈alkyl),alkoxyalkyl groups containing from three to eight carbon atoms (i.e.,C₃–C₈alkoxyalkyl), alkyl groups containing from one to eight carbonatoms where one of the carbon atoms is substituted with a hydroxyl group(i.e., C₁–C₈hydroxyalkyl), and aralkyl groups containing from seven totwelve carbon atoms (i.e., C₇–C₁₂aralkyl).

Alternatively, R₁ and R₂, when taken together with the nitrogen atom towhich they are directly attached in formula (I), may form a ring denotedby formula (II):

wherein the ring of formula (II) is formed from the nitrogen as shown aswell as three to nine additional ring atoms independently selected fromcarbon, nitrogen, oxygen, and sulfur; where any two adjacent ring atomsmay be joined together by single or double bonds, and where any one ormore of the additional carbon ring atoms may be substituted with one ortwo substituents selected from hydrogen, hydroxy, C₁–C₃hydroxyalkyl,oxo, C₂–C₄acyl, C₁–C₃alkyl, C₂–C₄alkylcarboxy, C₁–C₃alkoxy,C₁–C₂₀alkanoyloxy, or may be substituted to form a spiro five- orsix-membered heterocyclic ring containing one or two heteroatomsselected from oxygen and sulfur (e.g., an acetal, thioacetal, ketal, orthioketal group); and any two adjacent additional carbon ring atoms maybe fused to a C₃–C₈carbocyclic ring, and any one or more of theadditional nitrogen ring atoms may be substituted with substituentsselected from hydrogen, C₁–C₆alkyl, C₂–C₄acyl, C₂–C₄hydroxyalkyl andC₃–C₈alkoxyalkyl. Examples of substituents containing a fused ringsystem include the perhydroindolyl and 1,2,3,4-tetrahydroisoquinolinylgroups.

In connection with the ring of formula (II), any two adjacent ring atomsmay be joined together by single or double bonds. Thus, the ring offormula (II) may be saturated or unsaturated, and an unsaturated ringmay contain one, or more than one, sites of unsaturation. In otherwords, the ring of formula (II) may contain one or more double bonds, itbeing understood, however, that the unsaturated ring of formula (II) ischemically stable.

Alternatively, R₁ and R₂, when taken together with the 2-amino nitrogenof formula (I), may complete a bicyclic ring. Bicyclic rings include,for example, 3-azabicyclo[3.2.2]nonane, 2-azabicyclo[2.2.2]octane,3-azabicyclo[3.1.0]hexane, and 3-azabicyclo[3.2.0]heptane. For thesederivatives, the 2-substituents of the cycloalkyl cinnamides of formula(I) are the following groups: 3-azabicyclo[3.2.2]nonan-3-yl,2-azabicyclo[2.2.2]octan-2-yl, 3-azabicyclo[3.1.0]hexan-3-yl, and3-azabicyclo[3.2.0]heptan-3-yl.

Preferably for formula (II), R₁ and R₂, when taken together, containonly a single heteroatom. Preferred heteroatoms include nitrogen, oxygenand sulfur. An example of a ring in which R₁ and R₂ together include anoxygen heteroatom is the morpholinyl group. An example of a ring whereR₁ and R₂ together include a second nitrogen heteroatom is thepiperazinyl group.

Cycloalkyl substituents R₃ and R₄ may be independently attached to anyof the ring positions except positions 1 and 2 (e.g., both R₃ and R₄ maybe attached to the same ring position or each attached to different ringpositions). R₃ and R₄ are independently selected from hydrogen, hydroxy,C₁–C₆alkyl, and C₁–C₆alkoxy, and, when both R₃ and R₄ are attached tothe same cycloalkyl ring atom, may together form a spiro five- orsix-membered heterocyclic ring containing one or two heteroatomsselected from oxygen and sulfur. Preferred heterocyclic substituentscontain either a single oxygen or a single sulfur ring atom.

Depending upon the identity of X, the cinnamide side chain,

in formula (I) may take several forms. For example, a compound offormula (I) may have X as a —C(R₆,R₁₄)—Y— group, where Y may be any of adirect bond, an oxygen atom (O), a sulfur atom (S) or a C₁–C₄alkylenegroup. R₆ and R₁₄ are independently selected from hydrogen, C₁–C₆alkyl,aryl and benzyl, or R₆ and R₁₄, when taken together with the carbon towhich they are attached, may form a spiro C₃–C₅cycloalkyl. Thus,compounds of the invention include compounds of formula (I) where R₆ andR₁₄ are hydrogen and Y is a direct bond, such that X may be CH₂.

Alternatively, X may be a direct bond. Independent of the selections forA, X and other variables, R₅ is selected from hydrogen, C₁–C₆alkyl, aryland benzyl.

Cinnamide side chain component A is generally a hydrophobic moiety.Typically, a hydrophobic moiety is comprised of non-polar chemicalgroups such as hydrocarbons or hydrocarbons substituted with halogens orethers or heterocyclic groups containing nitrogen, oxygen, or sulfurring atoms. Suitable hydrocarbons are C₅–C₁₂alkyl and C₃–C₁₃carbocyclicrings. Particularly preferred cyclic hydrocarbons include selectedaromatic groups such as phenyl, 1-naphthyl, 2-naphthyl, indenyl,acenaphthyl, and fluorenyl and are represented by formulae (III), (IV),(V), (VI), (VII), or (VIII) respectively.

A suitable “A” group within the compounds of the present invention is aphenyl ring represented by formula (III):

where R₇, R₈ and R₉ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, aryl and N(R₁₅,R₁₆)where R₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl, and C₁–C₆alkyl.

For compounds of formula (I) where X is a direct bond or CH₂, at leastone of R₇, R₈ and R₉ is preferably selected from amine (—NR₁₅R₁₆, whereR₁₅ and R₁₆ are independently hydrogen, acetyl, methanesulfonyl, andC₁–C₆alkyl), bromine, chlorine, fluorine, carboxy, hydrogen, hydroxy,hydroxymethyl, nitro, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkylcarbonyl, C₁–C₆thioalkyl or aryl groups.

Other suitable “A” groups in compounds of the present invention are1-naphthyl groups as represented by formula (IV):

where R₁₀ and R₁₁ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, and N(R₁₅,R₁₆) whereR₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl, and C₁–C₆alkyl.

Other suitable “A” groups in compounds of the present invention are2-naphthyl group as represented by formula (V):

where R₁₀ and R₁₁ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, and N(R₁₅,R₁₆) whereR₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl, and C₁–C₆alkyl, as defined above.

Other suitable “A” groups in compounds of the present invention arearomatic groups represented by formula (VI):

where R₁₂ is selected from bromine, chlorine, fluorine, carboxy,hydrogen, hydroxy, hydroxymethyl, methanesulfonamido, nitro, sulfamyl,trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl, C₁–C₆alkoxy,C₂–C₇alkoxycarbonyl. C₁–C₆thioalkyl, and N(R₁₅,R₁₆) where R₁₅ and R₁₆are independently selected from hydrogen, acetyl, methanesulfonyl, andC₁–C₆alkyl; and Z is selected from CH, CH₂, O, N and S, where Z may bedirectly bonded to the carbon atom in formula (I) that is shown directlybonded to “A” when Z is CH or N, or Z may be directly bonded to R₁₇ whenZ is N, and R₁₇ is selected from hydrogen, C₁–C₆alkyl, C₃–C₈cycloalkyl,aryl and benzyl.

The aryl groups of formula (VI) are derivatives of indene, indole,benzofuran, and thianaphthene when Z is methylene, nitrogen, oxygen, andsulfur, respectively. Preferred heterocyclic groups of formula (VI)include indole where Z is NH, benzofuran where Z is 0, and thianaphthenewhere Z is S.

Another suitable “A” group in compounds of the present invention areacenaphthyl groups as represented by formula (VII):

Still another suitable “A” group in compounds of the present inventionis the fluorenyl group represented by formula (VIII):

Preferably, cinnamide side chain component A is an acenaphthyl orfluorenyl group only when X is a direct bond or CH₂. In furtherpreferred embodiments, the acenaphthyl group is a 1-acenaphthyl group,and the fluorenyl group is a 9-fluorenyl group.

As mentioned above, the present invention provides aminocycloalkylcinnamides represented by formula (I). In a preferred embodiment X is(CH₂)—Y. For these embodiments, Y is preferably a direct bond, an oxygenatom, or a sulfur atom. In a particularly preferred embodiment, Y is adirect bond or an oxygen atom. In another preferred embodiment Y is adirect bond and X is C(R₆,R₁₄), where R₆ and R₁₄ are as defined above.

The following are further preferred compounds of the present invention:

(1R,2R)/(1S,2S)-N-Methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]3,4-dichlorocinnamide monohydrochloride

Outline of Method of Preparation of Compounds of the Invention

The aminocycloalkyl cinnamide compounds of the present invention containamino and cinnamide sidechains disposed in a 1,2 arrangement on acycloalkyl ring. Accordingly, the amino and cinnamide sidechains may bedisposed in either a cis or trans relationship, relative to one anotherand the plane of the cycloalkyl ring. The present invention providessynthetic methodology whereby cis or trans compounds may be prepared.

The compounds of formula (I) may be synthesized in analogy with knownmethods, including those described in the following publications: B. R.de Costa et al., J. Med. Chem. 1989, 32, 1996; B. R. de Costa et al., J.Med. Chem. 1990, 33, 3100; and U.S. Pat. Nos. 4,579,863; 4,598,087;4,656,182; 4,663,343; 4,737,493; 4,855,316; 5,130,309, and 5,506,257.

Cinnamic acids may be prepared by known methods (see, e.g., J. R.Johnson in Organic Reactions; R. Adams Editor; 1942, Vol. 1, p. 218;John Wiley and Sons, Inc. New York).

The individual enantiomers may be obtained from mixtures of thedifferent forms by known methods of resolution, such as the isolation orformation of the diastereomers, followed by recrystallization.Alternatively, the pure enantiomeric forms can be obtained bypreparative chiral High Performance Liquid Chromatography (HPLC).

The synthetic procedures described herein, especially when taken withthe general knowledge in the art, provide sufficient guidance to thoseof ordinary skill in the art to perform the synthesis, isolation, andpurification of the compounds of the present invention.

Compositions and Modes of Administration

In another embodiment, the present invention provides compositions whichinclude a cycloalkylamine compound as described above in admixture orotherwise in association with one or more inert carriers, excipients anddiluents, as well as optional ingredients if desired. These compositionsare useful as, for example, assay standards, convenient means of makingbulk shipments, or pharmaceutical compositions. An assayable amount of acompound of the invention is an amount which is readily measurable bystandard assay procedures and techniques as are well known andappreciated by those skilled in the art. Assayable amounts of a compoundof the invention will generally vary from about 0.001 wt % to about 75wt % of the entire weight of the composition. Inert carriers include anymaterial which does not degrade or otherwise covalently react with acompound of the invention. Examples of suitable inert carriers arewater; aqueous buffers, such as those which are generally useful in HighPerformance Liquid Chromatography (HPLC) analysis; organic solvents suchas acetonitrile, ethyl acetate, hexane and the like (which are suitablefor use in in vitro diagnostics or assays, but typically are notsuitable for administration to a warm-blooded animal); andpharmaceutically acceptable carriers, such as physiological saline.

Thus, the present invention provides a pharmaceutical or veterinarycomposition (hereinafter, simply referred to as a pharmaceuticalcomposition) containing a cycloalkylamine compound as described above,in admixture with a pharmaceutically acceptable carrier, excipient ordiluent. The invention further provides a pharmaceutical compositioncontaining an effective amount of a cycloalkylamine compound asdescribed above, in association with a pharmaceutically acceptablecarrier.

The pharmaceutical compositions of the present invention may be in anyform which allows for the composition to be administered to a patient.For example, the composition may be in the form of a solid, liquid orgas (aerosol). Typical routes of administration include, withoutlimitation, oral, topical, parenteral, sublingual, rectal, vaginal, andintranasal. The term parenteral as used herein includes subcutaneousinjections, intravenous, intramuscular, epidural, intrasternal injectionor infusion techniques. Pharmaceutical composition of the invention areformulated so as to allow the active ingredients contained therein to bebioavailable upon administration of the composition to a patient.Compositions that will be administered to a patient take the form of oneor more dosage units, where for example, a tablet, capsule or cachet maybe a single dosage unit, and a container of cycloalkylamine compound inaerosol form may hold a plurality of dosage units.

Materials used in preparing the pharmaceutical compositions should bepharmaceutically pure and non-toxic in the amounts used. The inventivecompositions may include one or more compounds (active ingredients)known for a particularly desirable effect. For instance, epinephrine maybe combined with an aminocycloalkyl cinnamide compound of the invention,to provide a composition useful to induce local anesthesia. It will beevident to those of ordinary skill in the art that the optimal dosage ofthe active ingredient(s) in the pharmaceutical composition will dependon a variety of factors. Relevant factors include, without limitation,the type of subject (e.g., human), the particular form of the activeingredient, the manner of administration and the composition employed.

In general, the pharmaceutical composition includes a cycloalkylaminecompound as described herein, in admixture with one or more carriers.The carrier(s) may be particulate, so that the compositions are, forexample, in tablet or powder form. The carrier(s) may be liquid, withthe compositions being, for example, an oral syrup or injectable liquid.In addition, the carrier(s) may be gaseous, so as to provide an aerosolcomposition useful in, e.g., inhalatory administration.

When intended for oral administration, the composition is preferably ineither solid or liquid form, where semi-solid, semi-liquid, suspensionand gel forms are included within the forms considered herein as eithersolid or liquid.

As a solid composition for oral administration, the composition may beformulated into a powder, granule, compressed tablet, pill, capsule,cachet, chewing gum, wafer, lozenges, or the like form. Such a solidcomposition will typically contain one or more inert diluents or ediblecarriers. In addition, one or more of the following adjuvants may bepresent: binders such as syrups, acacia, sorbitol, polyvinylpyrrolidone,carboxymethylcellulose, ethyl cellulose, microcrystalline cellulose, gumtragacanth or gelatin, and mixtures thereof, excipients such as starch,lactose or dextrins, disintegrating agents such as alginic acid, sodiumalginate, Primogel, corn starch and the like; lubricants such asmagnesium stearate or Sterotex; fillers such as lactose, mannitols,starch, calcium phosphate, sorbitol, methylcellulose, and mixturesthereof; lubricants such as magnesium stearate, high molecular weightpolymers such as polyethylene glycol, high molecular weight fatty acidssuch as stearic acid, silica, wetting agents such as sodium laurylsulfate, glidants such as colloidal silicon dioxide; sweetening agentssuch as sucrose or saccharin, a flavoring agent such as peppermint,methyl salicylate or orange flavoring, and a coloring agent.

When the composition is in the form of a capsule, e.g., a gelatincapsule, it may contain, in addition to materials of the above type, aliquid carrier such as polyethylene glycol or a fatty oil.

The composition may be in the form of a liquid, e.g., an elixir, syrup,solution, aqueous or oily emulsion or suspension, or even dry powderswhich may be reconstituted with water and/or other liquid media prior touse. The liquid may be for oral administration or for delivery byinjection, as two examples. When intended for oral administration,preferred compositions contain, in addition to the present compounds,one or more of a sweetening agent, thickening agent, preservative (e.g.,alkyl p-hydoxybenzoate), dye/colorant and flavor enhancer (flavorant).In a composition intended to be administered by injection, one or moreof a surfactant, preservative (e.g., alkyl p-hydroxybenzoate), wettingagent, dispersing agent, suspending agent (e.g., sorbitol, glucose, orother sugar syrups), buffer, stabilizer and isotonic agent may beincluded. The emulsifying agent may be selected from lecithin orsorbitol monooleate.

The liquid pharmaceutical compositions of the invention, whether they besolutions, suspensions or other like form, may include one or more ofthe following adjuvants: sterile diluents such as water for injection,saline solution, preferably physiological saline, Ringer's solution,isotonic sodium chloride, fixed oils such as synthetic mono ordigylcerides which may serve as the solvent or suspending medium,polyethylene glycols, glycerin, propylene glycol or other solvents;antibacterial agents such as benzyl alcohol or methyl paraben;antioxidants such as ascorbic acid or sodium bisulfite; chelating agentssuch as ethylenediaminetetraacetic acid; buffers such as acetates,citrates or phosphates and agents for the adjustment of tonicity such assodium chloride or dextrose. The parenteral preparation can be enclosedin ampoules, disposable syringes or multiple dose vials made of glass orplastic. Physiological saline is a preferred adjuvant. An injectablepharmaceutical composition is preferably sterile.

A liquid compositions intended for either parenteral or oraladministration should contain an amount of the inventive compound suchthat a suitable dosage will be obtained. Typically, this amount is atleast 0.01% of a compound of the invention in the composition. Whenintended for oral administration, this amount may be varied to bebetween 0.1 and about 70% of the weight of the composition. Preferredoral compositions contain between about 4% and about 50% of the activecycloalkylamine compound. Preferred compositions and preparationsaccording to the present invention are prepared so that a parenteraldosage unit contains between 0.01 to 10% by weight of active compound.

The pharmaceutical composition may be intended for topicaladministration, in which case the carrier may suitably comprise asolution, emulsion, ointment, cream or gel base. The base, for example,may comprise one or more of the following: petrolatum, lanolin,polyethylene glycols, bee wax, mineral oil, diluents such as water andalcohol, and emulsifiers and stabilizers. Thickening agents may bepresent in a pharmaceutical composition for topical administration. Ifintended for transdermal administration, the composition may include atransdermal patch or iontophoresis device. Topical formulations maycontain a concentration of the inventive compound of from about 0.1 toabout 25% w/v (weight per unit volume).

The composition may be intended for rectal administration, in the form,e.g., of a suppository which will melt in the rectum and release thedrug. The composition for rectal administration may contain anoleaginous base as a suitable nonirritating excipient. Such basesinclude, without limitation, lanolin, cocoa butter and polyethyleneglycol. Low-melting waxes are preferred for the preparation of asuppository, where mixtures of fatty acid glycerides and/or cocoa butterare suitable waxes. The waxes may be melted, and the cycloalkylaminecompound is dispersed homogeneously therein by stirring. The moltenhomogeneous mixture is then poured into convenient sized molds, allowedto cool and thereby solidify.

The composition may include various materials which modify the physicalform of a solid or liquid dosage unit. For example, the composition mayinclude materials that form a coating shell around the activeingredients. The materials which form the coating shell are typicallyinert, and may be selected from, for example, sugar, shellac, and otherenteric coating agents. Alternatively, the active ingredients may beencased in a gelatin capsule or cachet.

The composition in solid or liquid form may include an agent which bindsto the cycloalkylamine compound and thereby assists in the delivery ofthe active components. Suitable agents which may act in this capacityinclude a monoclonal or polyclonal antibody, a protein or a liposome.

The pharmaceutical composition of the present invention may consist ofgaseous dosage units, e.g., it may be in the form of an aerosol. Theterm aerosol is used to denote a variety of systems ranging from thoseof colloidal nature to systems consisting of pressurized packages.Delivery may be by a liquefied or compressed gas or by a suitable pumpsystem which dispenses the active ingredients. Aerosols of compounds ofthe invention may be delivered in single phase, bi-phasic, or tri-phasicsystems in order to deliver the active ingredient(s). Delivery of theaerosol includes the necessary container, activators, valves,subcontainers, and the like, which together may form a kit. Preferredaerosols may be determined by one skilled in the art, without undueexperimentation.

Whether in solid, liquid or gaseous form, the pharmaceutical compositionof the present invention may contain one or more known pharmacologicalagents used in methods for either modulating ion channel activity in awarm-blooded animal or for modulating ion channel activity in vitro, orused in the treatment of arrhythmia, diseases of the central nervoussystem, convulsions, epileptic spasms, depression, anxiety,schizophrenia, Parkinson's disease, respiratory disorders, cysticfibrosis, asthma, cough, inflammation, arthritis, allergies,gastrointestinal disorders, urinary incontinence, irritable bowelsyndrome, cardiovascular diseases, cerebral or myocardial ischemias,hypertension, long-QT syndrome, stroke, migraine, ophthalmic diseases,diabetes mellitus, myopathies, Becker's myotonia, myasthenia gravis,paramyotonia congentia, malignant hyperthermia, hyperkalemic periodicparalysis, Thomsen's myotonia, autoimmune disorders, graft rejection inorgan transplantation or bone marrow transplantation, heart failure,hypotension, Alzheimer's disease and other mental disorders, andalopecia. Other agents known to cause libido enhancement, localanalgesia or anesthesia may be combined with compounds of the presentinvention.

The pharmaceutical compositions may be prepared by methodology wellknown in the pharmaceutical art. The aminocycloalkyl compounds of theinvention may be in the form of a solvate in a pharmaceuticallyacceptable solvent such as water or physiological saline. Alternatively,the compounds may be in the form of the free base or in the form of apharmaceutically acceptable salt such as the hydrochloride, sulfate,phosphate, citrate, fumarate, methanesulfonate, acetate, tartrate,maleate, lactate, mandelate, salicylate, succinate and other salts knownin the art. The appropriate salt would be chosen to enhancebioavailability or stability of the compound for the appropriate mode ofemployment (e.g., oral or parenteral routes of administration).

A composition intended to be administered by injection can be preparedby combining the cycloalkylamine compound with water, and preferablybuffering agents, so as to form a solution. The water is preferablysterile pyrogen-free water. A surfactant may be added to facilitate theformation of a homogeneous solution or suspension. Surfactants arecompounds that non-covalently interact with the cycloalkylamine compoundso as to facilitate dissolution or homogeneous suspension of thecycloalkylamine compound in the aqueous delivery system. Surfactants aredesirably present in aqueous compositions of the invention because thecycloalkylamine compounds of the present invention are typicallyhydrophobic. Other carriers for injection include, without limitation,sterile peroxide-free ethyl oleate, dehydrated alcohols, propyleneglycol, as well as mixtures thereof.

Suitable pharmaceutical adjuvants for the injecting solutions includestabilizing agents, solubilizing agents, buffers, and viscosityregulators. Examples of these adjuvants include ethanol,ethylenediaminetetraacetic acid (EDTA), tartrate buffers, citratebuffers, and high molecular weight polyethylene oxide viscosityregulators. These pharmaceutical formulations may be injectedintramuscularly, epidurally, intraperitoneally, or intravenously.

Pharmacological Testing

As noted above, the present invention provides for utilizing thecompounds described above in in vitro and in vivo methods. In oneembodiment, ion channels, such as cardiac sodium channels, are blockedin vitro or in vivo.

Ion channels are ubiquitous membrane proteins in the cells ofwarm-blooded animals such as mammals. Their critical physiological rolesinclude control of the electrical potential across the membrane,mediation of ionic and fluid balance, facilitation of neuromuscular andneuronal transmission, rapid transmembrane signal transduction, andregulation of secretion and contractility.

Accordingly, compounds that are capable of modulating the activity orfunction of the appropriate ion channels will be useful in treating orpreventing a variety of diseases or disorders caused by defective orinadequate function of the ion channels. The compounds of the inventionare found to have significant activity in modulating ion channelactivity both in vivo and in vitro.

Thus, the present invention provides for methods of treating a diseaseor condition in a warm-blooded animal suffering from or having thedisease or condition, and/or preventing a disease or condition fromarising in a warm-blooded animal, wherein a therapeutically effectiveamount of a compound of formula (I), or a composition containing acompound of formula (I) is administered to a warm-blooded animal in needthereof. The diseases and conditions to which the compounds,compositions and methods of the present invention may be applied asfollows: arrhythmia, diseases of the central nervous system, convulsion,epileptic spasms, depression, anxiety, schizophrenia, Parkinson'sdisease, respiratory disorders, cystic fibrosis, asthma, cough,inflammation, arthritis, allergies, gastrointestinal disorders, urinaryincontinence, irritable bowel syndrome, cardiovascular diseases,cerebral or myocardial ischemias, hypertension, long-QT syndrome,stroke, migraine, ophthalmic diseases, diabetes mellitus, myopathies,Becker's myotonia, myasthenia gravis, paramyotonia congentia, malignanthyperthermia, hyperkalemic periodic paralysis, Thomsen's myotonia,autoimmune disorders, graft rejection in organ transplantation or bonemarrow transplantation, heart failure, hypotension, Alzheimer's diseaseor other mental disorder, and alopecia.

Furthermore, the present invention provides a method for producing localanalgesia or anesthesia in a warm-blooded animal which includesadministering to a warm-blooded animal in need thereof an effectiveamount of a compound of formula (I) or a pharmaceutical compositioncontaining a compound of formula (I). These methods may be used torelieve or forestall the sensation of pain in a warm-blooded animal.

Furthermore, the present invention provides a method wherein apreparation that contains ion channels is exposed to, or a warm-bloodedanimal (e.g., a mammal, such as a human) is administered an effectiveamount of an aminocycloalkyl cinnamide compound of the invention.Suitable preparations containing cardiac sodium channels include cellsisolated from cardiac tissue as well as cultured cell lines. The step ofcontacting includes, for example, incubation of ion channels with acompound under conditions and for a time sufficient to permit modulationof the activity of the channels by the compound.

In another embodiment, the compounds described above are provided fortreating arrhythmia. As used herein, “treating arrhythmia” refers toboth therapy for arrhythmia and for the prevention of arrhythmiasoccurring in a heart that is susceptible to arrhythmia. An effectiveamount of a composition of the present invention is used to treatarrhythmia in a warm-blooded animal, such as a human. Methods ofadministering effective amounts of antiarrhythmic agents are well knownin the art and include the administration of an oral or parenteraldosage form. Such dosage forms include, but are not limited to,parenteral dosage form. Such dosage forms include, but are not limitedto, parenteral solutions, tablets, capsules, sustained release implants,and transdermal delivery systems. Generally, oral or intravenousadministration is preferred. The dosage amount and frequency areselected to attain effective levels of the agent without harmfuleffects. It will generally range from a dosage of from about 0.1 toabout 100 mg/kg/day, and typically from about 0.1 to 10 mg/kg whereadministered orally or intravenously for antiarrhythmic effect.

Administration of compositions of the present invention may be carriedout in combination with the administration of other agents. For example,it may be desired to administer an opioid antagonist, such as naloxone,if a compound exhibits opioid activity where such activity may not bedesired. The naloxone may antagonize opioid activity of the administeredcompound without adverse interference with the antiarrhythmic activity.As another example, an aminocycloalkyl cinnamide compound of theinvention may be co-administered with epinephrine in order to includelocal anesthesia.

In order to assess whether a compound of the present invention has adesired pharmacological activity, it is subjected to a series of tests.The precise test to employ will depend on the physiological response ofinterest. The published literature contains numerous protocols fortesting the efficacy of a potential therapeutic agent, and theseprotocols may be employed with the present compounds and compositions.

For example, in connection with treatment or prevention of arrhythmia, aseries of four tests may be conducted. In the first of these tests, acompound of the present invention is given as increasing (doubling witheach dose) intravenous boluses every 8 minutes to a pentobarbitalanesthetized rat. The effects of the compound on blood pressure, heartrate and the ECG are measured at 30 seconds, 1, 2, 4 and 8 minutes aftereach dose. Increasing doses are given until the animal dies. The causeof death is identified as being of either respiratory or cardiac origin.This test gives an indication as to whether the compound is modulatingthe activity of sodium channels and/or potassium channels, and inaddition gives information about acute toxicity. The indices of sodiumchannel blockade are increasing P-R interval and QRS widening of theECG. Potassium channel blockade results in Q-T interval prolongation ofthe ECG.

A second test involves administration of a compound as an infusion topentobarbital anesthetized rats in which the left ventricle is subjectedto electrical square wave stimulation performed according to a presetprotocol described in further detail below. This protocol includes thedetermination of thresholds for induction of extrasystoles andventricular fibrillation. In addition, effects on electricalrefractoriness are assessed by a single extra beat technique. Inaddition effects on blood pressure, heart rate and the ECG are recorded.In this test, sodium channel blockers produce the ECG changes expectedfrom the first test. In addition, sodium channel blockers also raise thethresholds for induction of extrasystoles and ventricular fibrillation.Potassium channel blockade is revealed by increasing refractoriness andwidening of the Q-T intervals of the ECG.

A third test involves exposing isolated rat hearts to increasingconcentrations of a compound. Ventricular pressures, heart rate,conduction velocity and ECG are recorded in the isolated heart in thepresence of varying concentrations of the compound. The test providesevidence for direct toxic effects on the myocardium. Additionally,selectivity, potency and efficacy of action of a compound can beascertained under conditions simulating ischemia. Concentrations foundto be effective in this test are expected to be efficacious in theelectrophysiological studies.

A fourth test is estimation of the antiarrhythmic activity of a compoundagainst the arrhythmias induced by coronary artery occlusion inanaesthetized rats. It is expected that a good antiarrhythmic compoundwill have antiarrhythmic activity at doses which have minimal effects oneither the ECG, blood pressure or heart rate under normal conditions,and preferably on all these parameters.

All of the foregoing tests are performed using rat tissue. In order toensure that a compound is not having effects which are only specific torat tissue, further experiments are performed in dogs and primates. Inorder to assess possible sodium channel and potassium channel blockingaction in vivo in dogs, a compound is tested for effects on the ECG,ventricular epicardial conduction velocity and responses to electricalstimulation. An anesthetized dog is subjected to an open chest procedureto expose the atrial and ventricular epicardium. After the pericardiumis removed from the heart a recording/stimulation electrode is sewn ontothe epicardial surface of the atria and ventricle. Using this array, andsuitable stimulation protocols, conduction velocity across theepicardium as well as responsiveness to electrical stimulation can beassessed. This information coupled with measurements of the ECG allowsone to assess whether sodium and/or potassium channel blockade occurs.As in the first test in rats, a compound is given as a series ofincreasing bolus doses. At the same time possible toxic effects of acompound on the dog's cardiovascular system are assessed.

The effects of a compound on the ECG and responses to electricalstimulation are also assessed in intact, anesthetized monkeys (Macacafascilaris). In this preparation, a blood pressure cannula and ECGelectrodes are suitably placed in an anesthetized baboon. In addition, astimulating electrode is placed onto the atria and ventricle, togetherwith monophasic action potential electrodes. As in the tests describedabove, ECG and electrical stimulation response to a compound reveal thepossible presence of sodium and/or potassium channel blockade. Themonophasic action potential also reveals whether a compound widens theaction potential, an action expected of a potassium channel blocker.

As another example, in connection with the mitigation or prevention ofthe sensation of pain, the following test may be performed. To determinethe effects of a compound of the present invention on an animal'sresponse to a sharp pain sensation, the effects of a slight prick from a7.5 g weighted syringe fitted with a 23G needle applied to the shavedback of a guinea pig (Cavia porcellus) is assessed followingsubcutaneous administration of (e.g. 50 μl, 10 mg/ml) a solution of thecompound in saline to raise a visible bleb on the skin. Each test isperformed on the central area of the bleb and also on its periphery toascertain the diffusion of the test solution from the point ofadministration. If the test animal produces a flinch in response to thestimulus, this demonstrates the absence of blockade of pain sensation.Testing is performed at intervals for up to 4 hours post administration.The sites of bleb formation are examined after 24 hours to determine ifskin abnormalities arise from the local administration of testsubstances or the vehicle (e.g. saline) used in the preparation of thetest solutions.

Other Compositions

The present invention also provides kits that contain a pharmaceuticalcomposition which includes one or more compounds of the above formulae.The kit also includes instructions for the use of the pharmaceuticalcomposition for modulating the activity of ion channels, for thetreatment of arrhythmia or for the production of local analgesia and/oranesthesia, and for the other utilities disclosed herein. Preferably, acommercial package will contain one or more unit doses of thepharmaceutical composition. For example, such a unit dose may be anamount sufficient for the preparation of an intravenous injection. Itwill be evident to those of ordinary skill in the art that compoundswhich are light and/or air sensitive may require special packagingand/or formulation. For example, packaging may be used which is opaqueto light, and/or sealed from contact with ambient air, and/or formulatedwith suitable coatings or excipients.

The following examples are offered by way of illustration and not by wayof limitation. In the Examples, and unless otherwise specified, startingmaterials were obtained from well-known commercial supply houses, e.g.,Aldrich Chemical Company (Milwaukee, Wis.), and were of standard gradeand purity. “Ether” and “ethyl ether” both refers to diethyl ether; “h.”refers to hours; “min.” refers to minutes; “GC” refers to gaschromatography; “v/v” refers to volume per volume; and ratios are weightratios unless otherwise indicated.

EXAMPLES Example 1 Preparation of Compound 1(1R,2R)/(1S,2S)-N-Methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]3,4-dichlorocinnamide monohydrochloride

The synthetic sequence of this Example is shown in FIG. 1A.

Acid chloride formation: 3,4-dichlorocinnamic acid (5 g, 23 mmol,Aldrich cat. #14,470-3) was refluxed in thionyl chloride (12 mL, BDHcat. #30417) under nitrogen for 1 h. At first the white solid did notdissolve, but became pinkish. After refluxing the solution became clearand almost colorless. After the mixture was stirred at room temperaturefor a further 1 h, the thionyl chloride was removed in vacuo (using 3×5mL CCl₄). The product was then dissolved in dichloromethane (10 mL).

Amide formation: the above acid chloride solution was added via cannulato a cooled solution of the racemic diamine,(1R,2R)/(1S,2S)-N-Methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-amine(prepared according to U.S. Pat. No. 4,579,863 and J. Med. Chem., 1982,25, 1125) (4 g, 22 mmol) in dichloromethane (10 mL) under nitrogen. Themixture was stirred at 0° C. for 10 min., and then at room temperaturefor 1 h. Ether (15 mL) was added and a thick white precipitate formed.The crude hygroscopic product (9.7 g) was filtered off and washed withether (2×10 mL). It was recrystallized from hot ethyl acetate-methanol,to give 2 crops of white crystalline solid (7.5 g), which were dried byheating in vacuo to 60° C. for 3 h. A third crop of cream colored solidwas also obtained (0.9 g). The flocculent precipitate was filtered offand washed with ether and dried in vacuo. NMR indicated that thecombined first two crops contained ethyl acetate, so they wererecrystallized from hot methanol (7 mL) -ether, to give 1st crop (5.3g); 2nd crop (0.85 g). Dried in vacuo at 60° C. for 4 h. Yield of pureproduct (67%).

IR, and ³C-NMR spectra were recorded for solutions in CDCl₃.

Microanalysis: C, 55.60; H, 6.54; N, 6.41% (theoretical forC₂₀H₂₇N₂OCl₃: C 57.50, H 6.51, N 6.70%).

Example 2 Preparation of Compound 2(1R,2R)/(1S,2S)-N-[2-(4-Morpholinyl)cyclohexyl] 3,4-dichlorocinnamidemonohydrochloride

The synthetic sequence of this Example is shown in FIG. 1B.

Acid chloride formation: To 3,4-dichlorocinnamic acid (2.17 g, 10 mmol,Aldrich Cat. # 14,470-3) under nitrogen was added thionyl chloride (10mL, Aldrich Cat. # 32,054-4). The reaction mixture was refluxed for 1hour and then 30 min. at room temperature. The excess of thionylchloride was removed in vacuo to leave a greenish solid which wasdissolved in dichloromethane (10 mL).

NH Amide formation: To the chilled (0° C.) solution of(1R,2R)/(1S,2S)-[2-(4-morpholinyl)cyclohexyl]amine (1.75 g, 9.5 mmol) indichloromethane was added via cannula the above acid chloride solution.Upon completion of the addition the reaction mixture was allowed to warmup to room temperature and was stirred overnight. GC analysis showedthat the reaction was completed. The solvent was evaporated in vacuo,the residue taken up with ether and triturated, evaporation in vacuo ofthe solvent afforded a pink solid. The crude salt was partitionedbetween 1N aqueous NaOH (50 mL) and dichloromethane (50 mL). The organiclayer was collected and dried over sodium sulfate. Evaporation in vacuoof the solvent afforded an oil which was dissolved in ether (50 mL) andtreated with a HCl saturated solution of ether (50 mL). The resultantprecipitate was collected and rinsed with ether (2×50 mL).Recrystallization in ethanol yielded 1.86 g of the desired product.

Microanalysis: C, 54.31; H, 6.89; N, 5.90% (theoretical forC₁₉H₂₅N₂O₂Cl₃.1.0C₂H₅OH C, 54.14; H, 6.71; N, 6.01%

Example 3 Preparation of Compound 3(1R,2R)/(1S,2S)-N-Methyl-N-[2-(1-pyrrolidinyl)cyclopentyl]3,4-dichlorocinnamidemonohydrochloride

The synthetic sequence of this Example is shown in FIG. 1C.

Acid chloride formation: 3,4-dichlorocinnamic acid (2.71 g, 12.5 mmol,Aldrich cat. #14,470-3) was refluxed in thionyl chloride (10 mL, Aldrichcat. #32,054-4) under nitrogen for 2 h. After the reaction mixture wasstirred at room temperature for a further 1 h., the thionyl chloride wasremoved in vacuo (using 3×5 mL CCl₄) to give an off-white solid, whichwas dissolved in dichloromethane (8 mL).

Amide formation: the acid chloride solution was added via cannula to aroom temperature solution of (1R,2R)/(1S,2S)-N-methyl-N-[2-(1-pyrrolidinyl)cyclopentyl]-amine (2.0 g, 11.9mmol) in dichloromethane (8 mL) under nitrogen. The reaction was stirredat room temperature for 1 h. Ether (30 mL) was slowly added to thereaction mixture, causing the formation of an orange/brown oil. Thesolvent was removed in vacuo and the residue was dissolved in 1N aq. HCl(100 mL). The aqueous layer was washed with ether (1×60 mL. 2×30 mL),and then was basified (pH 12) by the addition of 50% aq. NaOH solution.A yellow oil was formed, and the aqueous/oil mixture was extracted withdichloromethane (1×60 mL, 2×40 mL). The combined dichloromethaneextracts were dried over sodium sulphate and the solvent was removed invacuo. The residue (4.3 g) was purified by column chromatography (silicagel, methanol eluant). The isolated product was dissolved in 1N aq. HCl(60 mL), and NaCl (12 g) was added to the resultant solution, which wasthen extracted with chloroform (3×60 mL). The chloroform extracts werecombined and dried over sodium sulphate. The solvent was removed invacuo. The crude HCl salt (5.35 g) was recrystallized from hot hexane(25 mL)/hot acetone (40 mL). The solution was slowly cooled to roomtemperature and left at ˜5° C. for two days. Two crops of recystallizedproduct were collected, rinsed with ether, and dried in vacuo. Wt. of1st crop: 3:91 g, 2nd crop: 0.14 g. The former was used for compoundcharacterization.

IR, and ¹³C-NMR spectra were recorded for solutions in CDCl₃. The NMRindicated the presence of two isomers (1:1).

Microanalysis: C, 56.46; H, 6.15; N, 6.79% (theoretical forC₁₉H₂₅N₂OCl₃; C, 56.52; H, 6.24; N, 6.94%).

Example 4 Assessment of Antiarrhythmic Efficacy

Antiarrhythmic efficacy was assessed by investigating the effect of acompound on the incidence of cardiac arrhythmias in conscious ratssubjected to coronary artery occlusion. Rats weighing 200–300 gms weresubjected to preparative surgery and assigned to groups in a randomblock design. In each case, the animal was anesthetized with halothaneduring surgical preparation. The left femoral artery was cannulated formeasurement of mean arterial blood pressure and withdrawal of bloodsamples. The left femoral vein was also cannulated for injection ofdrugs. The thoracic cavity was opened and a polyethylene occluderloosely placed around the left anterior descending coronary artery. Thethoracic cavity was then closed. ECG was recorded by insertion ofelectrodes placed along the anatomical axis of the heart. All cannulaeand electrode leads were exteriorized in the mid scapular region. In arandom and double-blind manner, about 0.5 to 2 hours post-surgery, aninfusion of vehicle, or the compound to be tested was given. After 5 to15 minutes infusion, the occluder was pulled so as to produce coronaryartery occlusion. ECG, arrhythmias, blood pressure, heart rate andmortality were monitored for 30 minutes after occlusion. Arrhythmiaswere recorded as ventricular tachycardia (VT) and ventricularfibrillation (VF) and scored according to Curtis, M. J. and Walker, M.J. A., Cardiovasc. Res. 22:656 (1988) (see Table 1).

TABLE 1 Score Description 0 0–49 VPBs 1 50–499 VPBs 2 >499 VPBs and/or 1episode of spontaneously reverting VT or VF 3 >1 episode of VT or VF orboth (>60s total combined duration) 4 VT or VF or both (60–119s totalcombined duration) 5 VT or VF or both (>119s total combined duration) 6fatal VF starting at >15 min after occlusion 7 fatal VF starting atbetween 4 min and 14 min 59s after occlusion 8 fatal VF starting atbetween 1 min and 3 min 59s after occlusion 9 fatal VF starting <1 minafter occlusion Where: VPB = ventricular premature beats VT =ventricular tachycardia VF = ventricular fibrillation

Rats were excluded from the study if they did not exhibit pre-occlusionserum potassium concentrations within the range of 2.9–3.9 mM. Occlusionis associated with increases in R-wave height and “S-T” segmentelevation; and an occluded zone (measured after death by cardiogreen dyeperfusion) in the range of 25%–50% of total left-ventricular weight.

Table 2 describes the result of tests of the compounds described thereinas values of a given infusion rate in micromol/kg/min. (ED₅₀AA) whichwill reduce the arrhythmia score in treated animals to 50% of that shownby animals treated only with the vehicle in which the test drug(s) isdissolved.

TABLE 2 Compound ED₅₀AA #1 0.4 #2 ND #3 2   ND = Not Determined

Example 5 Measurement of ECG Parameters

Rats weighing 200–250 gms were used in this example. Animals wereanesthetized with 60 mg/kg pentobarbital i.p. The carotid artery andjugular vein were cannulated for measurement of blood pressure and druginjection, respectively. ECG was recorded by insertion of electrodesplaced along the anatomical axis of the heart. All compounds were givenas bolus injections.

Various ECG parameters were measured. Table 3 describes the results ofthe tests as ED₂₅ (micromol/kg) which are the doses required to producea 25% increase in the parameter measured (ne=not estimated). Theincreases in P-R interval and QRS interval indicate cardiac sodiumchannel blockage while the increase in Q-T interval indicates ancillarycardiac potassium channel blockage which is the property of a type 1aantiarrhythmic.

TABLE 3 Compound PR QRS QT #1 2.8 ND 8 #2 60 64 9 #3 8 12 5 ND = NotDetermined

Example 6 Assessment of Sodium Channel Blockage

Rats were prepared according to the preceding procedure. Two silverstimulating electrodes were inserted through the chest wall andimplanted in the left ventricle. Square wave stimulation was used todetermine threshold current for capture, ventricular fibrillationthreshold current, and effective refractory period (Howard, P. G. andWalker, M. J. A., Proc. West. Pharmacol. Soc. 33:123–127 (1990)). Table4 contains ED₂₅ values for these indices of cardiac sodium channelblockage, where the ED₂₅ is the infusion rate in micromol/kg/minute ofcompound required to elicit a 25% increase from control. The increasesin refractoriness indicate ancillary blockage of potassium channels. Thethreshold current for capture is represented by “It”. The fibrillationthreshold current is represented by “VFT”. The effective refractingperiod is represented by “ERP”.

TABLE 4 Compound It VFT ERP #1 0.8 0.7 1.4 #2 12 3 4 #3 4 12 2

Example 7 Canine Vagal-AF Model

General Methods

Mongrel dogs of either sex weighing 1549 kg were anesthetized withmorphine (2 mg/kg im initially, followed by 0.5 mg/kg IV every 2 h) andα-chloralose (120 mg/kg IV followed by an infusion of 29.25 mg/kg/h;St.-Georges et al., 1997). Dogs were ventilated mechanically with roomair supplemented with oxygen via an endotracheal tube at 20 to 25breaths/minute with a tidal volume obtained from a nomogram. Arterialblood gases were measured and kept in the physiological range (SAO₂>90%,pH 7.30–7.45). Catheters were inserted into the femoral artery for bloodpressure recording and blood gas measurement, and into both femoralveins for drug administration and venous sampling. Catheters were keptpatent with heparinized 0.9% saline solution. Body temperature wasmaintained at 37–40° C. with a heating blanket.

The heart was exposed via a medial thoracotomy and a pericardial cradlewas created. Three bipolar stainless steel, Teflon™-coated electrodeswere inserted into the right atria for recording and stimulation, andone was inserted into the left atrial appendage for recording. Aprogrammable stimulator (Digital Cardiovascular Instruments, Berkeley,Calif.) was used to stimulate the right atrium with 2 ms, twicediastolic threshold pulses. Two stainless steel, Teflon™-coatedelectrodes were inserted into the left ventricle, one for recording andthe other for stimulation. A ventricular demand pacemaker (GBM 5880,Medtronics, Minneapolis, Minn.) was used to stimulate the ventricles at90 beats/minute when (particular during vagal-AF) the ventricular ratebecame excessively slow. A P23 ID transducer, electrophysiologicalamplifier (Bloom Associates, Flying Hills, Pa.) and paper recorder(Astromed MT-95000, Toronto, ON, Canada) were used to record ECG leadsII and III, atrial and ventricular electrograms, blood pressure andstimulation artefacts. The vagi were isolated in the neck,doubly-ligated and divided, and electrodes inserted in each nerve (seebelow). To block changes in β-adrenergic effects on the heart, nadololwas administered as an initial dose of 0.5 mg/kg iv, followed by 0.25mg/kg IV every two hours.

Atrial Fibrillation Model

Drug effects to terminate sustained AF maintained during continuousvagal nerve stimulation were assessed. Unipolar hook electrodes(stainless steel insulated with Teflon™, coated except for the distal1–2 cm) were inserted via a 21 gauge needle within and parallel to theshaft of each nerve. In most experiments, unipolar stimuli were appliedwith a stimulator (model DS-9F, Grass Instruments, Quincy, Mass.) set todeliver 0.1 ms square-wave pulses at 10 Hz and a voltage 60% of thatrequired to produce asystole. In some experiments, bipolar stimulationwas used. The voltage required to produce asystole ranged between 3–20volts. Under control conditions, a short burst of rapid atrial pacing(10 Hz, four times diastolic threshold) was delivered to induce AF whichwas ordinarily sustained for more than 20 minutes. The vagal stimulationvoltage was adjusted under control conditions, and then readjusted aftereach treatment to maintain the same bradycardic effect. AF was definedas rapid (>500 minute under control conditions), irregular atrial rhythmwith varying electrogram morphology.

Measurement of Electrophysiological Variables and Vagal Response

Diastolic threshold current was determined at a basic cycle length of300 ms by increasing the current 0.1 mA incrementally until stablecapture was obtained. For subsequent protocols current was set to twicediastolic threshold. Atrial and ventricular ERP was measured with theextrastimulus method, over a range of S1S2 intervals at a basic cyclelength of 300 ms. A premature extrastimulus S2 was introduced every 15basic stimuli. The S1 S2 interval was increased in 5 ms increments untilcapture occurred, with the longest S1S2 interval consistently failing toproduce a propagated response defining ERP. Diastolic threshold and ERPwere determined in duplicate and averaged to give a single value. Thesevalues were generally within 5 ms. The interval between the stimulusartefact and the peak of the local electrogram was measured as an indexof conduction velocity. AF cycle length (AFCL) was measured duringvagal-AF by counting the number of cycles (number of beats −1) over a2-second interval at each of the atrial recording sites. The three AFCLsmeasurements were averaged to obtain an overall mean AFCL for eachexperimental condition.

The stimulus voltage-heart rate relationship for vagal nerve stimulationwas determined under control conditions in most experiments. The vagalnerves were stimulated as described above with various voltages todetermine the voltage which caused asystole (defined as a sinus pausegreater than 3 seconds). The response to vagal nerve stimulation wasconfirmed under each experimental condition and the voltage adjusted tomaintain the heart rate response to vagal nerve stimulation constant. Incases in which is was not possible to produce asystole, vagal nervestimulation was adjusted to a voltage which allowed two 20-minuteepisodes of vagal-AF to be maintained under control conditions (seebelow).

Experimental Protocols

Some of the experimental groups studied are summarized in Table 5. Eachdog received only one drug at doses indicated in Table 5. The firstseries of experiments were dose ranging studies, followed by blindedstudy in which 1–3 doses were given. All drugs were administered IV viaan infusion pump, with drug solutions prepared freshly in plasticcontainers on the day of the experiment. Vagal stimulation parameterswere defined under control conditions as described above, andmaintenance of AF during 20 minutes of vagal nerve stimulation undercontrol conditions was verified. After the termination of AF, thediastolic threshold and ERP of the atrium and ventricle were determined.Subsequently, these variables were reassessed in the atrium under vagalnerve stimulation. Electrophysiological testing usually took 15–20minutes. The heart rate response to vagal nerve stimulation wasconfirmed and the vagal-AF/electrophysiological testing protocol wasrepeated. A pre-drug blood sample was obtained and vagal-AFreinstituted. Five minutes later, one of the treatments was administeredat doses shown in Table 5. The total dose was infused over 5 minutes anda blood sample obtained immediately thereafter. No maintenance infusionwas given. If AF terminated within 15 minutes, the electrophysiologicalmeasurements obtained under control conditions were repeated and a bloodsample was obtained. If AF was not terminated by the first dose (within15 minutes), a blood sample was obtained and vagal stimulation wasdiscontinued to allow a return to sinus rhythm. The electrophysiologicalmeasurements were repeated and a third and final blood sample for thisdose was obtained. AF was reinitiated and the vagal-AF/druginfusion/electrophysiological testing protocol was repeated until AF wasterminated by the drug.

Statistical Analysis

Group data are expressed as the mean ±SEM. Statistical analysis wascarried out for effective doses for AFCL, and ERP using a t-test with aBonferroini correction for multiple comparisons. Drug effects on bloodpressure, heart rate, diastolic threshold and ECG intervals wereassessed at the median dose for termination of AF. Two tailed tests wereused and a p<0.05 was taken to indicate statistical significance.

TABLE 5 EXPERIMENTAL GROUPS AND DOSES OF DRUGS Dose Mean dose Mediandose range Effective doses required for required for tested forterminating termination of termination of Drug (μmol/kg) AF (μmol/kg) AF(μmol/kg) AF (μmol/kg) Flecainide 1.25–10 4–2.5; 1–10  4 ± 2 2.5 Com-0.25–20 1.5; 4–10; 1–20 11 ± 2 10 pound 1A single drug was administered to each dog over the dose range specifieduntil AF was terminated. The number of dogs in which AF was terminatedat each dose is shown (number of dogs-dose, in μmol/kg). The mean±SEM aswell as the median dose required to terminate AF is shown. Each dogreceived only one drug.Results

The two drugs (flecainide and Compound 1) did not reduce blood pressureor heart rate at the median dose for termination of vagal-AF. The heartrate response to vagal nerve stimulation was similar in all groups andwas not influenced by any of the drugs tested. Vagal nerve stimulationat 60% of the voltage required to produce asystole (10±1 V) produced a1.3±0.1 second pause. The two drugs tested were effective, but theefficacy for terminating AF was greater for Compound 1 (6/6 dogs; 100%)than for flecainide (5/6 dogs; 80%) (Table 5). The dose required toterminate AF depended on the drug considered (Table 5). AFCL wasprolonged prior to AF termination in all cases. Drug effects on AFCLlength were dose related and doses that were effective in terminating AFproduced greater increases in AFCL than those that did not.

The conversion rates for the drugs tested in the vagal-AF model werecomparable to those found for Class I drugs in this model (Wang et al.,1991, Wang J., Bourne G. W., Wang Z., Villemaire C., Talajic M., NattelS., Circulation. 88(3):1030–44, 1993) and those found clinically (seeNattel S., Hadjis T., Talajic M., Drugs. 48(3):345–71, 1994, orSteinbeck G., Remp T., Hoffmann E., Journal of CardiovascularElectrophysiology. 9(8 Suppl):S104–8, 1998, for a review). Flecainideterminated AF in 5/6 dogs consistent with its published efficacy (WangZ., Page P., Nattel S., Circulation Research. 71(2):271–87, 1992). Theefficacy of Compound 1 was higher than that reported for low dosesotalol (2 mg/kg iv) but comparable to high dose sotalol (8 mg/kg iv;Wang J., Bourne G. W., Wang Z., Villemaire C., Talajic M., Nattel S.,Circulation. 88(3):1030–44, 1993), ambasilide and azimilide (Nattel S.,Cardiovascular Research. 37(3):567–77, 1998).

AFCL has been used as an index of atrial ERP during AF. All of the drugstested in the present study prolonged AFCL during vagal nervestimulation. Flecainide prolonged AFCL to a similar degree in thepresent study to that reported previously (Wang Z., Page P., Nattel S.,Circulation Research. 71(2):271–87, 1992). The increases in AFCLproduced by Compound 1 prior to termination of AF were similar to thoseseen with sotalol, dofetilide, azimilide, and ambasilide in previousstudies (see Wang J., Feng J., Nattel S., Circulation. 90(4):2032–40,1994; Nattel, S., Cardiovascular Research. 37(3):567–77, 1998).Drug-induced increases of 60–100 ms appear to be associated with AFtermination in this model. In about 60% of the dogs studied. AF wasinduced during the determination of ERP in the presence of vagal nervestimulation. No differences were noted between drugs for preventinginitiation of AF in this setting. In dogs in which AF was induced undercontrol conditions, flecainide prevented induction in 2/4 while Compound1 prevented induction in 4/5. After completing the electrophysiologicaltesting, it was possible to induce AF in all dogs with the exception of2/6 dogs in the Compound 1 group. Note that reinduction attempts tookplace after a period of time sufficient to permit significant drugredistribution and lower plasma concentrations.

At effective doses, both drugs tested prolonged atrial ERP. In allcases, ERP was reduced during vagal nerve stimulation. Compound 1 alsoprolonged atrial ERP more during vagal nerve stimulation.

In summary, the results of this study demonstrate the effectiveness ofCompound 1 for terminating AF in the canine vagal-AF model. Theconversion rates are similar to those reported for a variety of otherclass I and III drugs in this model. The effectiveness of flecainide inthe present study was comparable to that previously reported. All of thedrug prolonged AFCL prior to termination of AF; effects which areglobally consistent with the wave length of reentry model fortermination of AF. The dosing regimen was not optimized.

Example 8 Canine Sterile Pericarditis Model

This model has been used to characterize the mechanisms of AF and atrialflutter (AFL). Waldo and colleagues have found that AF depends onreentry and that the site of termination is usually an area of slowedconduction. This canine model is prepared by dusting the exposed atriawith talcum powder followed by “burst” pacing the atria over a period ofdays after recovery. AF is inducible two days after surgery, however, bythe fourth day after surgical preparation; sustainable atrial flutter isthe predominant inducible rhythm. The inducibility of AF at day 2 issomewhat variable, such that only 50% of dogs may have sustained AF(generally <60 minutes) for a requisite of 30 minutes. However, thesustainable atrial flutter that evolves by the fourth day is induciblein most preparations. Atrial flutter is more readily “mapped” forpurposes of determining drug mechanisms. Inducibility of AF subsidesafter the fourth day post-surgery, similar to the AF that often developsfollowing cardiac surgery that the sterile pericarditis model mimics.There may be an inflammatory component involved in the etiology ofpost-surgery AF that would provide a degree of selectivity to anischaemia or acid selective drug. Similarly, while coronary arterybypass graft (CABG) surgery is performed to alleviate ventricularischaemia, such patients may also be at risk for mild atrial ischaemiadue to coronary artery disease (CAD). While atrial infarcts are rare,there has been an association between AV nodal artery stenosus and riskfor AF following CABG surgery. Surgical disruption of the autonomicinnervation of the atria may also play a role in AF following CABG.

Methods

Studies were carried out in a canine model of sterile percarditis todetermine the potency and efficacy of Compound 1 in terminating atrialfibrillation/flutter. Atrial flutter or fibrillation was induced 2 to 4days after creation of sterile pericarditis in adult mongrel dogsweighing 19 kg to 25 kg. In all instances, the atrial fibrillation orflutter lasted longer than 10 minutes. All studies were performed inaccordance with guidelines specified by our Institutional Animal Careand Use Committee, the American Heart Association Policy on ResearchAnimal Use, and the Public Health Service Policy on Use of LaboratoryAnimals.

Creation of the Sterile Pericarditis Atrial Fib/Flutter Model

The canine sterile pericarditis model was created as previouslydescribed. At the time of surgery, a pair of stainless steel wireelectrodes coated with FEP polymer except for the tip (O Flexon, Davisand Geck) were sutured on the right atrial appendage, Bachman's bundleand the posteroinferior left atrium close to the proximal portion of thecoronary sinus. The distance between each electrode of each pair wasapproximately 5 mm. These wire electrodes were brought out through thechest wall and exteriorized posteriorly in the interscapular region forsubsequent use. At the completion of surgery, the dogs were givenantibiotics and analgesics and then were allowed to recover.Postoperative care included administration of antibiotics andanalgesics.

In all dogs, beginning on postoperative day 2, induction of stableatrial fibrillation/flutter was attempted in the conscious, non-sedatedstate to confirm the inducibility and the stability of atrialfib/flutter and to test the efficacy of the drugs. Atrial pacing wasperformed through the electrodes sutured during the initial surgery. Onpostoperative day 4, when stable atrial flutter was induced, theopen-chest study was performed.

For the open-chest study, each dog was anesthetized with pentobarbital(30 mg/kg IV) and mechanically ventilated with 100% oxygen by use of aBoyle model 50 anesthesia machine (Harris-Lake, Inc.). The bodytemperature of each dog was kept within the normal physiological rangethroughout the study with a heating pad. With the dog anesthetized, butbefore the chest was opened, radiofrequency ablation of the His bundlewas performed to create complete atrioventricular (AV) block by standardelectrode catheter techniques. This was done to minimize thesuperimposition of atrial and ventricular complexes during subsequentrecordings of unipolar atrial electrograms after induction of atrialflutter. After complete AV block was created, an effective ventricularrate was maintained by pacing of the ventricles at a rate of 60 to 80beats per minute with a Medtronic 5375 Pulse Generator (Medtronic Inc.)to deliver stimuli via the electrodes sutured to the right ventricleduring the initial surgery.

Determination of Stimulus Thresholds and Refractory Periods DuringPacing

For the induction of AF/AFL, one of two previously described methods wasused: (1) introduction of one or two premature atrial beats after atrain of 8 paced atrial beats at a cycle length of 400 ms, 300 ms, 200ms, or 150 ms, or (2) rapid atrial Pacing for Periods of 1 to 10 secondsat rates incrementally faster by 10 to 50 beats per minute than thespontaneous sinus rate until atrial flutter was induced or there was aloss of 1:1 atrial capture. Atrial pacing was performed from either theright atrial appendage electrodes or the posteroinferior left atrialelectrodes. All pacing was performed using stimuli of twice thresholdfor each basic drive train with a modified Medtronic 5325 programmable,battery-powered stimulator with a pulse width of 1.8 ms.

After the induction of stable atrial fib/flutter (lasting longer than 10minutes), the atrial fib/flutter cycle length was measured and theinitial mapping and analysis were performed to determine the location ofthe atrial fib/flutter reentrant circuit. Atrial flutter was defined asa rapid atrial rhythm (rate, >240 beats per minute) characterized by aconstant beat-to-beat cycle length, polarity, morphology, and amplitudeof the recorded bipolar electrograms.

Drug Efficacy Testing Protocol

1. Effective refractory periods (ERPs) were measured from three sites:right atrial appendage (RAA), posterior left atrium (PLA), and Bachman'sBundle (BB), at two basic cycle lengths 200 and 400 ms.

2. Pace induce A-Fib or AFL. This was attempted for one hour. If noarrhythmia was induced, no further study was done on that day.

3. If induced, AF must have been sustained for 10 minutes. Then awaiting period was allowed for spontaneous termination or 20 minutes,whichever came first.

4. AF was then reinduced and 5 minutes was allowed before starting druginfusion.

5. Drug was then infused in a bolus over 5 minutes.

6. If AF terminated with the first dose then a blood sample was takenand ERP measurements were repeated.

7. Five minutes was allowed for the drug to terminate. If there was notermination then the second dose was given over 5 minutes.

8. After termination and ERPs were measured, a second attempt toreinduce AF was tried for a period of ten minutes.

9. If reinduced and sustained for 10 minutes, a blood sample was takenand the study repeated from #3 above.

10. If no reinduction, then the study was over.

Results

The effect of Compound 1 on 2 episodes of AFL and 3 episodes of AF wererecorded, and one out of those three episodes of AF was reinductionafter first dose. Both episodes of AFL terminated during administrationof the first dose (10 μmol/kg; average actual amount delivered=3.5μmol/kg), and also all three episodes of AF terminated duringadministration of the first dose (10 μmol/kg; average actual amountdelivered=7 μmol/kg). None of these episodes of AFL could be reinduced.There was no significant change in thresholds and effective refractoryperiods (ERPs) before and after drug, determined by the paired t-test.No adverse effects were noted.

Compound 1 was effective in terminating episodes of atrialfibrillation/flutter in this model. A prolongation in atrial fib/fluttercycle length (AFCL) generally preceded termination of the arrhythmia.Limited effects on atrial refractory periods measured after arrhythmiatermination may have been due to pharmacokinetic redistribution at thetime of measurement. There was no proarrhythmia or cardiovascularadverse events seen during drug treatment.

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually incorporated by reference.

From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A compound of formula (I), or a solvate or pharmaceuticallyacceptable salt thereof:

wherein, independently at each occurrence, n is selected from 1, 2, 3and 4; X is a direct bond, Y is a direct bond; R₁₃ is selected fromhydrogen, C₁–C₆alkyl, C₃–C₈cycloalkyl, aryl, and benzyl; R₁ and R₂ aretaken together with the nitrogen atom to which they are directlyattached in formula (I) to form a morpholinyl ring and where any one ormore of the carbon ring atoms in the morpholinyl ring may be substitutedwith one or two substituents selected from hydrogen, hydroxy,C₁–C₃hydroxyalkyl, oxo, C₂–C₄acyl, C₁–C₃alkyl, C₂–C₄alkylcarboxy,C₁–C₃alkoxy, C₁–C₂₀alkanoyloxy, or may be substituted to form a spirofive- or six-membered heterocyclic ring containing one or twoheteroatoms selected from oxygen and sulfur; and any two adjacent carbonring atoms in the morpholinyl ring may be fused to a C₃–C₈carbocyclicring; R₃ and R₄ are independently attached to the cycloalkyl ring shownin formula (I) at other than the 1 and 2 positions and are independentlyselected from hydrogen, hydroxy, C₁–C₆alkyl, and C₁–C₆alkoxy; R₅ ishydrogen, C₁–C₆alkyl, aryl and benzyl; and A is selected fromC₅–C₁₂alkyl, a C₃–C₁₃carbocyclic ring, and a ring system of formulae(III):

where R₇, R₈ and R₉ are independently selected from bromine, chlorine,fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido,nitro, sulfamyl, trifluoromethyl, C₂–C₇alkanoyloxy, C₁–C₆alkyl,C₁–C₆alkoxy, C₂–C₇alkoxycarbonyl, C₁–C₆thioalkyl, aryl and N(R₁₅,R₁₆)where R₁₅ and R₁₆ are independently selected from hydrogen, acetyl,methanesulfonyl, and C₁–C₆alkyl; including isolated enantiomeric,diastereomeric and geometric isomers thereof, and mixtures thereof.
 2. Amixture of (1R,2R)-N-[2-(4-morpholinyl)cyclohexyl]-3,4-dichlorocinnamidemonohydrochloride and(1S,2S)-N-[2-(4-morpholinyl)cyclohexyl]-3,4-dichlorocinnamidemonohydrochloride, and pharmaceutically acceptable salts and solvatesthereof.
 3. A composition comprising a pharmaceutically acceptablecarrier, excipient or diluent and a compound according to claim 1 orclaim
 2. 4. A pharmaceutical composition comprising a pharmaceuticallyacceptable carrier, diluent, or excipient and a therapeuticallyeffective amount of a compound according to claim 1 or claim
 2. 5. Apharmaceutical composition comprising a pharmaceutically acceptablecarrier, diluent, or excipient and an amount of a compound effective toprovide therapy for arrhythmia in a warm-blooded animal, wherein thecompound is a compound according to claim 1 or claim
 2. 6. A compoundselected from the group consisting of(1R,2R)-N-[2-(4-morpholinyl)cyclohexyl]-3,4-dichlorocinnamidemonohydrochloride and(1S,2S)-N-[2-(4-morpholinyl)cyclohexyl]-3,4-dichlorocinnamidemonohydrochloride, and pharmaceutically acceptable salts and solvates ofany of the foregoing.